A burglar alarm is a technical installation for both facility and personal protection. One of its main tasks, aside from registering an alarm, is to alert the police or the assigned security service. The communication between the different units of the system, such as sensor and warning device, can be achieved by three different means:
1) DC technology via electric lines
2) bus conncection on data lines or
3) radio systems.
The fundamental frequency of the alternating electric and magnetic fields depend on the communication technology: For the first two categories, it is 50 Hz respectively 60 Hz and for the third 433 or 868 MHz.
|magnetic flux density||0.13 µT (maximum)||-||at a distance of 50 cm |